1. Field of the Invention
This invention relates to an information retrieval system, and more particularly to an information retrieval system which retrieves desired information at a high speed from various data bases such as a file system.
2. Description of the Related Art
As well known in the art, since information retrieval processing of an information retrieval system is performed using a large amount of resources of a computer such as a central processing unit (CPU), a memory and input/output (I/O) apparatus, the load to the computer sometimes becomes very heavy, resulting in a drop of the speed of retrieval.
Thus, in an ordinary information retrieval system, hardware for exclusive use for information retrieval and so forth is added to reduce the load to the computer in order to achieve improvement in speed of retrieval.
However, even where hardware for exclusive use for information retrieval is added as described above, as the scale of a data base which makes an object of retrieval such as, for example, a text base which holds text documents such as news papers and patent documents has a large scale, the speed of retrieval is decreased still from a limitation in retrieval capacity of the hardware. Further, addition of such hardware for exclusive use for information retrieval is very disadvantageous also in terms of the cost.
Further, generally since an information retrieval system is basically a sequential system, that is, a system wherein comparison and determination processing of information in a text base and information to be retrieved is effected sequentially to perform retrieval, it has another subject to be solved in that, for example, when a plurality of users must simultaneously utilize the system to retrieve a plurality of text bases or a like case, the speed of retrieval is decreased remarkably.